X-ray tubes for microphotography



Nov. 15, 1966 KIYOSHI KITAHAMA ETAL 3,236,112

X-RAY TUBES FOR MICROPHOTOGRAPHY 5 Sheets-Sheet 1 Filed Jan. 8, 1963 ill Nov 15, 1966 KIYOSHI KITAHAMA ETAL 3,

X-RAY TUBES FOR MICROPHOTOGRAPHY Filed Jan. 8, 1963 5 Sheets-Sheet 2 Nov. 15, 1966 KIYOSHI KITAHAMA ETAL. 3,286,112

X-RAY TUBES FOR MICHOPHOTOGRAPHY Filed Jan. 8, 1963 3 Sheets-Sheet 3 (B) (C) p (F) 4 5 I (A) 4 5 5 J 5 4 4 5 4,5 g

United States Patent Ofifice 3,Z86,l l2 Patented Nov. 15, 1966 3,286,112 X-RAY TUBES FOR MICROPHOTOGRAPHY Kiyoshi Kitahama, 1054 Shimonagaya-cho, Minami-ku, Yokohama, Japan, and Tsuruko Kitahama, Minami-ku, Yokohama, Japan; said Tsuruko Kitahama assignor to said Kiyoshi Kitahama Filed Jan. 8, 1963, Ser. No. 250,126 Claims priority, application Japan, Jan. 10, 1962, 37/648; Sept. 12,1962, 37/39,268 5 Claims. (Cl. 31356) The present invention relates to microphoto X-ray tubes, and particularly novel and useful X-ray tubes of a relatively simple construction, wherein the heat resisting capacity of foci is increased by displaying microfocus action, thereby enabling significant utilization of a large amount of X-ray.

Hitherto, an X-ray generating mechanism of a microphoto X-ray tube of the type referred to above has been so adapted that electron beams issuing from cathodes are reduced to a small point under action of electric field or electromagnetic action form microfine X-ray foci whereby the electron beams impinge against anode targets of plane sheet or needle form. In such an X-ray focus reducing method, electron beams are very fine and long while being reduced to a small size. As a result, electric current passing through the tube is limited. Consequently, X-ray generation becomes small, and the amount of X- ray is not sufiicient to be advantageously utilized for X-ray microscopes. Furthermore, when a sufiicient amount of X-ray is intended to be generated, the foci can be disadvantageously destroyed by locally concentrated impact from the electron beams.

In accordance with the present invention, all the abovementioned disadvantages have been removed, and a microphoto X-ray tube is provided for utilizing a large amount of X-ray with safety and stability, which amount is increased by hundred or several hundred fold, as compared with the prior method for generating X-ray for the microphotography. The present invention comprises two adjacent and parallel arranged anodes forming a fine, elongated clearance therebetween, cathode electrodes adjacent to such fine clearance and disposed on either side of the anodes, and fine X-ray foci being formed by using such fine elongated clearance as a target, whereby only X-ray generated in the major axis of the target at the foci is utilized.

Thus, according to the present invention, the X-ray foci are formed in a fine elongation in two series of targets and accordingly the fine elongated foci form, whose area is much larger as compared with microfine X-ray foci for microphotography formed merely on targets of a plane sheet or needle form, receive impact from a large amount of electron beams and can provide an X-ray tube for microphotography which generates a large amount of electron beams in proportion to the foci area.

It should also be noted that, according to the present invention, an anode head is divided into two portions, wherein targets are formed on the anodic divisional surfaces, and accordingly, heat generated on such targets is transmitted over the large volume of anodic bodies and, since such targets have a large heat capacity and are not destroyed even on account of impact from a large amount of electron beams, this invention provides X-ray tubes for microphotography which have high safety and durability.

Moreover, according to the present invention, since electron beams are designed to impinge upon the entirety of fine targets, remarkably long filaments may be used as compared with those for conventional microphoto X-ray tubes. In addition, the thickness of such a filament need not be as thin as the conventional one. For example, the length of a filament which has been approximately 5 mm. max. may be elongated to above approximately 50 mm. according to this invention. Thus, a relatively large amount of electric current may be passed through the X-ray tube and, as a result, the tube current may be increased, thereby generating the abundant amount of X-ray necessary and suflicient for X-ray microphotography.

It should also be noted that, since X-ray is being utilized in the major axis of the target, a fine elongated foci formed on such target appear as reduced to a smaller size, as viewed from the body to be photographed, which means that reactional foci of X-ray tubes become smaller; accordingly, as the reactional foci of X-ray tubes are contracted and utilized as such, a clearer photographing may be obtained in the present X-ray tube for the micro photographing.

Furthermore, according to the present invention, as the targets are constructed symmetrically with respect to the central axis of X-rays utilized, the X-ray utilized will be enhanced in strength, clarity as well as homogeneity, and thus a microphoto X-ray tube having no so-called astigmatism phenomenon may be provided which is suitable for microphotographing.

In the present invention, as X-ray penetrates finally through microsmall perforations and is utilized, the reactional foci are further reduced to the size of microper-foras tions. In general, accordingly, it is possible to provide a microphoto X-ray tube in which the X-ray tube may be imparted with a further microfine focus reducing action. In this case, the practical final sizes for the reactional foci are below approximately 10 3.

According to the present invention, when X-ray is utilized as passed through microfine perforations, the loss of X-ray occurring as passed through such a microfine perforation may be of a relatively small extent and X-ray may be utilized at high efiiciency in the new microphoto X-ray tubes because the reactional foci of targets have been already reduced.

It is possible in the present invention, to provide small ously provide for safe and exact microphoto X-ray tubes. foci and impart to them a large capacity and simultaneously provide for safe and exact microphoto X-ray tubes. In this case, if the X-ray tubes are not used for microscopically enlarged photographing purpose, but used for general precision inspection, X-ray as referred to above need not be used.

- In the following, the present invention is further described in detail in connection with embodiments shown in the accompanying drawings, only by way of example. However, it is of course possible to make many appropriate modifications, unless they are not departing from the spirit and scope of the present invention as defined in the appended claims. In the drawings:

FIG. 1 is a schematic sectional elevation of a microphoto X-ray tube according to the present invention;

FIG. 2 is a sectional view taken along line 11-11 of FIG. 1;

FIGS. 3 and 4 are similar views with FIG. 2 illustrating a modified embodiment of this invention;

FIGS. 5, 6 and 7 are oblique views for different types of embodiments, showing relationship between anodic targets and an X-ray penetrating perforation in X-ray tubes;

FIGS. 8(A) to (F) are schematic plan views showing variations of forms of targets in X-ray tubes;

FIGS. 9(A) to (F) are schematic plan views shxowing variations in forms of target openings;

FIG. 10 is a front view of a cathode electron beam in the X-ray tube;

FIG. 11 is a schematic oblique view illustrating a modified form of a rotary anode target in the X-ray tube.

As is shown in FIGS. 1 to 4, 1 shows an anodic body and 2 a cathodic body respectively. The anodic body 1 possesses one head portion divided into two portions 1 and 1 by one strip clearance 3. Wall surfaces forming the clearance 3 constitute respective X-ray targets 4 and 5. In the cathodic body 2, cathodic head portions 6 and 7 are formed respectively and, as shown in FIG. 1 and FIG. 2, long filaments 8 and 9 are respectively disposed therein so as to be outwardly displaced from both sides of the anodic body 1 opposite the clearance 3. The filaments 8 and 9 may be supported in cathodic head portions 6 and 7 by any suitable means and such filaments may be at the same or at a different potential as the head portions depending on the particular requirements of series or parallel connections therefor. An X-ray passage It) is provided in the cathodic body 2 along the major axis of the clearance 3 forming the anodic target which has a mrcrofine pin hole or slit 11 forming an X-ray penetrating perforation, through which X-ray passes. Thus, even 1f, for instance, a geometrical small hole is stuffed with thin films of X-ray penetrating substance, such a hole is a penetrating perforation for X-rays. The entire assembly is enclosed within a wall 12 defining the X-ray tube.

Thus, when electric current is passed through the X- ray tube of the construction according to the present in- Vention, electron beams generated from filaments 8 and 9 of the cathodic body 2 will impinge upon the anodic targets 4 and 5, and appear as being reduced into a flat strip form by means of an electric field caused by the collimating cathode head portions 6 and 7. Thus, the collimating cathode portions 6 and 7 will focus cathode rays or electrons emitted from the filaments 8 and 9 on to fine, elongated X-ray foci along the target surfaces 4 and 5. Then, X-ray generated at the foci is utilized on the major axis, which is in the direction of the target, and discharged outside the tube through X-ray perforation 11 and passage 10 in order to be utilized for the microphotography. The V-shaped target defined by the surfaces 4 and directs the X-rays out through the perforation 11. This is apparent from the cross-sectional view of FIG. 2; and if another section were taken below line IIII of FIG. 1, it would show a larger distance between the anodes 1 and 1 The closer the cross-section is to the aperture 11, the larger the distance becomes. Accordingly, the X-rays are directed to the aperture 11 because of the V-shape of the target. The target need not, however, be V-shaped as will become apparent in the subsequent discussion of FIG. 8. It is only necessary that the two anodic head portions be contacting or joined at the ends furthest removed from the aperture 11.

The microphotographing X-ray tube according to this invention may be modified in various ways. For example, the anodic target in the embodiment shown in FIG. 1 possesses anodic head portions 1 and 1 which are made in a wedge form, and the clearance 3 of a diverging V- form as illustrated in FIG. 5. As illustrated in FIGS. 3 and 4, the wedge-form targets 1 and 1 made of tungsten or the like, are embedded in divided anodic head-portions 1 and 1 for instance, of copper of high heat conductance. The anodic head-portions 1 and 1 are provided with holes 13 or grooves 14 for circulating cooling fluids such as for instance, oil, water, air or other appropriate fluids for ensuring a high durability of said both anodic head portions.

As is illustrated in FIG. 11, the anodic head portion may be made in two cylindrical bodies 15 and 15 said two cylindrical bodies being rotated about the axes 16 and 16 by any suitable means, and electron beams may be made to impinge along fine long portions of contacting peripheral portion of such two cylindrical bodies. Such rotary anodes may generate an abundant amount of y With Safety as compared with above-mentioned stationary anodes,

The target may be constituted in various forms, as illustrated in FIGS. 8(A) to (F), of which cross-sectional forms are convex, rectangular, semi-circular, elliptical and other quadratic curves. Moreover, the shape of a clearance may be selected in various ways as shown in FIGS. 9(A) to (F). In this case, the clearance shown in FIG. 9(E) is made of a crystalline substance, and when the major axis of such crystalline body is adapted to be arranged in the X-ray utilization direction, a target may be formed which enables to further reduce actional foci.

In addition, the X-ray tube according to this invention may be provided with cathodes having filaments, which are provided each on both sides of the anodes in abovementioned embodiment, though a plurality of the filaments or cathodes may also be used. Thus, when a plurality set of filaments are provided, a further abundant amount of electric current may be passed and thus X-ray may also be generated in abundance. Moreover, electron sheaves 2 of the cathodic body 2 girding the filaments may effectively be formed in accordance with the shape of the target. For instance, if the shape of the target takes V-form, the shape of said electron sheaves may be effectively formed in V-shape as illustrated in FIG. 10. On the other hand, the microfine X-ray penetrating perforation 11 may be circular, elliptical or ovalform as shown in FIG. 5. As shown in FIG. 6, a fine and long hole or a slit may be selected. Furthermore, as shown in FIG. 7, two slits 11 and 11 may be crossed. The anode surfaces 4 and Sin FIGS. 5 and 7 diverge from each other along the clearance 3 resulting in a generally V-shaped target whereas the anode surfaces 4 and 5 in FIG. 6 are constantly spaced from each other resulting in a generally U-shaped target.

Furthermore, the present invention may not be limited to X-ray tubes, but also readily applicable as a highly eflicient radiating energy source for other radiating ray tubes.

What we claim is:

1. An X-ray tube for microphotography comprising two adjacent and substantially parallel arranged anodes closely spaced to define a fine, elongated gap therebetween, the proximate surfaces of said anodes tapering toward one another and constituting X-ray targets, said anodes having adjacent ends contacting each other, a pair of cathodes disposed on either side of said anodes and parallel to said elongated gap, said cathodes having spaced collimating cathodic head portions extending along said gap, and a filament in each head portion having a length corresponding to the length of said elongated gap, whereby cathode rays emitted from the filaments and collimated by said head portions are directed to said X-ray targets and X-rays are directed along the longitudinal axis of said gap away from the contacting ends of said anodes.

2. The invention as recited in claim 1 wherein an X- ray aperture in a wall of said tube is disposed in a path coaxial with the longitudinal axis of said elongated gap.

3. The invention as recited in claim 1 wherein said target surfaces diverge from each other whereby said elongated gap is V-shaped.

4. The invention as recited in claim 1 wherein said target surfaces are parallel and joined at one end thereof whereby said elongated gap is U-shaped.

5. The invention as recited in claim 1 wherein said anodes are cylindrical bodies rotatable on their longitudinal axes and being spaced from each other to define the elongated gap between their rotating surfaces.

References Cited by the Examiner UNITED STATES PATENTS lO/1937 Thaller 3l3-330 X 10/1956 Atlee 313-56 GEORGE N. WESTBY, DAVID G. GALVIN,

P. C. DEMEO, Assistant Examiners. 

1. AN X-RAY TUBE FOR MICROPHOTOGRAPHY COMPRISING TWO ADJACENT AND SUBSTANTIALLY PARALLEL ARRANGED ANODES CLOSELY SPACED TO DEFINE A FINE, ELONGATED GAP THEREBETWEEN THE PROXIMATE SURFACES OF SAID ANODES TAPERING TOWARD ONE ANOTHER AND CONSTITUING X-RAY TARGETS, SAID ANODES HAVING ADJACENT ENDS CONTACTING EACH OTHER, A PAIR OF CATHODES DISPOSED ON EITHER SIDE OF SAID ANODES AND PARALLEL TO SAID ELONGATED GAP, SAID CATHODES HAVING SPACED COLLIMATING CATHODIC HEAD PORTIONS EXTENDING ALONG SAID GAP, AND A FILAMENT IN EACH HEAD PORTION HAVING A LENGTH CORRESPONDING TO THE LENGTH OF SAID ELONGATED GAP, WHEREBY CATHODE RAYS EMITTED FROM THE FILAMENTS AND COLLIMATED BY SAID HEAD PORTIONS ARE DIRECTED TO SAID X-RAY TARGETS AND X-RAYS ARE DIRECTED ALONG THE LONGITUDINAL AXIS OF SAID GAP AWAY FROM THE CONTACTING ENDS OF SAID ANODES. 